I don’t mean drilling as in training ( I’m sure that’ll be another post), but drilling as in: taking out a drill and putting a hole in a wall to make an anchor point. It’s just not something that I’ve heard talked about in the fire service rope rescue community as a viable option for anchoring. I’m not sure why though.
We’re pretty comfortable putting holes in roofs, breaking windows, forcing doors, etc… We might even be comfortable drilling holes for anchors in a building collapse situation in order to lift a slab of concrete. Bet when it comes to rope rescue; No Way! Maybe that will change in the future.
Looking at bolting initially, I was surprised by how relatively simple and quick it is to do. There is no voodoo knowledge or ninja rope skills required. The key points are to drill to the correct depth, far enough away from an edge, and to get the dust out of the hole before inserting the bolt. All of that information is available from the bolt manufacturer. In the video below, I’m using a 1/2″ diameter 3 1/2″ length Hilti KB3 rated at over 6000 pounds of pullout force. The Fixe hanger is rated to over 6000 lbs as well. Those aren’t bad numbers. Drop in a couple of more for your system and you have a pretty bomber system with very little effort. Before, a blank concrete slab was a thing to for the urban rescuer to fear. Now, it could be looked at as something to seek out!
Keep an eye out when you walk through buildings on routine calls. Look around for the concrete columns and beams to see where you could drill. I did this and was amazed at where I now feel comfortable knowing I can set up a system.
As seen in the video below, it takes roughly two minutes to drill and clean the hole, set the bolt and hanger, and finally torque it to spec. There are some tricks to keep you from cranking on the nut too much if you don’t have a torque wrench, like using a stubby box wrench. You just can’t get the kind of leverage needed to overtighten unless you are REALLY cranking on it.
So get out there and start drilling!
[wpvideo BCF9Ybo8]
I think the LDT (large diameter tapcon) would be an avenue to really pursue in this realm as there are no torque issues to worry about and they are removable when you are done. Ratings are actually greater in pullout than in shear as well….
Mike, I think you’re right about the LDT’s. I still have the one’s you sent and am waiting for the right place to sink them. I forgot about the benefit of them not having to be torqued, just tightened. I’ll put the LDT’s on my short list of things to look into.
I watch that video and all I hear is Me, Me, Me. Screwing the nut on the end of the bolt until its flush will also help keep it from mushrooming as you hit it. I’m sure someone’s asking “Why not just wrap the pole?” Precast tilt up walls and post-tensioned ceiling sections are good canditiates for bolting. I wish we could drill more where I work. Thanks for the video.
Thanks for reading the blog, Tiim; the tip about screwing the nut on is a good one. After reading the Hilti literature again it looks as though the head is designed to be hit with a hammer without issue. I won’t reshoot video of that though. It would be obvious to anybody watching that I can’t swing a hammer to save my life if I had to do full swings!
It probably would be a better idea to wrap this column in an actual incident rather than bolt it. This bolt was sunk because it is easier to set up for training in the firehouse.
Drilling (training) is a matter of taking the hard right over the easy wrong. It’s certainly easier to kick back in the lazy boy, but you’ll never better yourself as a rescuer. HR/EW
Thanks for taking the time to comment, Chief.
What type of wall anchor did you use? Is it a rock climbing anchor? How are those rated for setting up rigging going horizontal or is there any difference? Also would like to here more about the LDT’s you guys are talking about above. I think this is a good topic to discuss as a different option in the urban environment where you may not be able to wrap a strap.
I used a 3 1/2″ Hilti KB3 with a rated pullout of 6300 lbs. I used a Fixe rock climbing hanger, rated at 30kN (6700 lbs) as the piece to where the actual carbiner connects. The ratings are different in pullout and in shear, but not by a huge amount in this application.
More to follow in the near future about the use of Large Diameter Tapcon (LDT) in all sorts of different configurations. Thanks for posting!